“Internationally Adopted Adults Who Did Not Suffer Severe Early Deprivation: The Role of Appraisal of Adoption,” published in Children and Youth Services Review (Volume 32, Issue 1 February 2010).
An adoption study of the psychological adjustment of 53 adults adopted from Greece to the Netherlands without early deprivation found their general well-being and self-esteem were comparable to the general population, though adopted men reported more depression. The average age at adoption was 9 months and the average age at the time of the study was 20. Factors related to lower mental health scores included search status (those who searched reported more mental health problems), no current partner (lower well-being); and a negative appraisal of adoption (more mental health problems and lower well-being). Note that this was a very small study and that these children had very good pre-adoption care, but the result support what almost all research shows, that adopted people compare favorably on psychological test with non adopted people.